Chapter 2: Specimen Collection and Processing Flashcards
What is the most common procedure performed in the area of parasitology the examination of a stool specimen?
Ova & Parasites
It refers to the egg stage of select parasites
Ova
It encompasses the other morphologic forms that may be present.
Parasites
What are the TWO general components associated with this routine parasitology
procedure?
Macroscopic & Microscopic
This examination is used to detect the presence of parasites in a stool specimen
This examination consist of THREE possible components, each of which is detailed in the sections that follow a discussion of collection, transport, and fixatives for preservation.
Microscopic examination
This examination was used to determine the consistency and color of the sample
Macroscopic examination
This stage is a morphologic form that invades humans.
Infective stage
This stage is one or more forms that can be detected via laboratory retrieval methods.
Diagnostic stage
This may be detected from a properly collected and prepared stool specimen.
Protozoa and Helminths
The protozoan forms are known as?
Trophozoites & Cysts
The typical stool collection protocol consists of how many specimens?
3 specimens in 10 days
What is the one exception in the diagnosis of amebiasis?
6 specimens in 14 days are acceptable
Stool samples from patients whose therapy includes?
- Bismuth
- Barium
- Mineral oil
Stool samples from patients whose therapy includes barium, bismuth, or mineral oil should be collected prior to therapy or not until how many days?
5 to 7 days after the completion of therapy
The collection of specimens from patients who have taken antibiotics or antimalarial medications should be delayed for how many weeks?
2 weeks following therapy
The acceptable amount of stool required for parasite study is?
2-5 grams or the size of the walnut
Urine should not be allowed to contaminate the stool specimen because it has been known to?
Destroy some parasites
Rice watery stool is known as what disease?
Cholera
What do you call when you cough up blood from your lungs?
Hemoptysis
What item should be specimen placed for transport to the laboratory?
Into a zip-lock plastic bag
This should also be used in laboratories, when present.
Biohazard hoods
To demonstrate the motility of protozoan trophozoites, what should be required?
Fresh specimen
Trophozoites are usually found in?
Liquid stool
In how many minutes does the liquid specimen be examined?
30 minutes
In how many hours does a soft or semiformed specimen yield a mixture of protozoan cysts and trophozoites be examined?
1 hour
Formed stool specimens are not likely to contain trophozoites; therefore, they can be held for how many hours?
24 hours
This are substances that preserves the morphology of protozoa and prevent further development of certain helminth eggs and larvae.
Fixatives
The specimen must be fixed in the preservative for at least how many minutes before processing begins?
30 minutes
This has been used for many years as an all-purpose fixative for the recovery of protozoa and helminths.
Formalin
Two concentrations of formalin are commonly used, how many percent of concentration?
5%
The concentration preserves helminth eggs and larvae, how many percent?
10%
Formalin may be routinely used for direct examinations and concentration procedures, except?
But not for permanent smears
What are the THREE primary advantages of the use of formalin?
- It is easy to prepare
- It preserves specimens for up to several years
- It has a long shelf life
What are the disadvantages of formalin?
It does not preserve parasite morphology
adequately for permanent smears.
How many percentages of parasite specimens are on feces stool?
95%
What is the early morning specimen that is best or most concentrated?
Sputum
What is the early morning or first void specimen?
Urine
What type of preservation is best for amoebic trophozoites can prepare permanent stain slides from specimens preserved?
Polyvinyl Alcohol (PVA)
What is the viable alternative to the use of PVA and Schaudinn fixative?
This preservative can be used for performing concentration techniques and permanent stained smears.
Sodium Acetate Formalin (SAF)
This type of preservative is used for fresh stool samples that are good for trophs and cysts.
Schaudinn’s fluid
The other alternatives to mercury-based PVA are the use of substitute compounds containing copper sulfate or zinc sulfate.
Modified Polyvinyl Alcohol (MPA)
These single-vial fixatives are free of formalin and mercury and can be used for concentration techniques and permanent stained smears.
Alternative single-vial system
It is a disk that is inserted into the eyepiece of the microscope.
Ocular micrometer
It is defined as a slide made by mixing a small portion of unfixed stool.
Direct wet mount
Screening a slide using these adjustments typically takes an experienced laboratory technician approximately how many minutes?
10 minutes
It is used to detect small numbers of parasites that might not be detected using direct wet preparations.
Concentration techniques
What are the TWO types of concentration techniques?
- Formalin-Ethyl Acetate Sedimentation
- Zinc Sulfate Flotation Technique
What is the most widely used sedimentation technique?
Formalin-Ethyl Acetate Sedimentation
This technique is also based on differences in specific gravity between the sample debris.
Zinc Sulfate Flotation Technique
What are the two common stains used for routine O&P testing including trichrome?
- Wheatley modification
- Iron hematoxylin
What is the most widely used permanent stain?
Wheatley trichrome
It is used instead of the trichrome technique.
Iron hematoxylin
It is used to diagnose cryptosporidium, isopora, and cyclospora.
Acid-fast stain
It is used to diagnose microsporidiosis.
Modified trichrome stain
It is used for blood smears.
Wright stain & Giemsa stain
It is easy to perform and most commonly used.
Trichrome stain
It can enhance the detection of microfilarial sheaths.
Iron hematoxylin
In Duodenal material, the specimen
may be collected by?
Nasogastric intubation or Enteric capsule test (Enterotest)
What are the parasites that may be observed in Duodenal material?
- Giardia intestinal
- Strongyloides stercoralis
- Cryptosporidium spp
Examination of sigmoidoscopy (colon) material is often helpful for detecting what parasite?
Entamoeba histolytica
The cellophane tape prep is the specimen of choice for the detection of what parasite?
Enterobius vermicularis
Parasites that may be recovered in the blood include?
- Malaria
- Leishmania donovani
- Trypanosoma spp
It is designed to concentrate blood specimens suspected of containing low numbers of microfilariae.
Knott techniques
It is a layer of white blood cells between the plasma and red blood cells that results from centrifuging whole blood.
Buffy coat slides
It is a slant inoculated by the addition of
a single drop of collected blood or ground tissue
Novy-MacNeal-Nicolle
Skin Snips are useful in the detection of what parasite?
Onchocercus volvulus
It is a technique used for the diagnosis of Chagas’ disease.
Xenodiagnosis
These techniques allow the detection of a wide variety of parasites but are labor-intensive and require an experienced microscopist.
Stool screening method
Tissue and biopsy specimens are recommended for the recovery of a number of parasites, including intracellular organisms such as?
- Toxoplasma gondii
- Leishmania spp.
Sputum
Parasite detection –>
- Paragonimus westermani
- Ascaris lumbricoides
- Strongyloides stercoralis
- Microsporidia
- Entamoeba histolytica
- Entamoeba gingivalis
Urine and Genital Secretions
Parasite detection –>
- Schistosoma haematobium
- Trichomonas vaginalis
Eye specimens
Parasite detection –>
- Acanthamoeba keratitis
- Acanthamoeba
- Toxoplasma gondii
- Microsporidia
- Loa loa
Mouth Scrapings and Nasal Discharge
Parasite detection –>
- Entamoeba gingivalis
- Trichomonas tenax
- Naegleria fowleri
Skin snips
Parasite detection –>
- Onchocerca volvulus
Cerebrospinal Fluid
Parasite detection –>
- Naegleria fowleri
Muscles
Parasite detection –>
- Trypanosoma cruzi
- Trichinella spiralis
Liver & Spleen
Parasite detection –>
- Entamoeba histolytica
- Leishmania donovani
Parasites that can be isolated with culture include
- Leishmania spp
- Entamoeba histolytica
- Trichomonas vaginalis
- Trypanosoma cruzi
- Toxoplasma gondii
These methods are not a common means of detecting parasites.
Culture methods
Animal inoculation and Xenodiagnosis specimens should be collected using?
Aseptic techniques
